1. Field of the Invention
The present invention relates to a swallowing assist device.
2. Disclosure of Related Art
In recent years, pneumonia has been exponentially increasing as a cause of death from disease. Most of pneumonic diseases resulting in death are aspiration pneumonia caused by so-called “aspiration.” In particular, aspiration pneumonia in elderly people has been a severe problem. The “aspiration” refers to a disease state in which swallowing cannot be done appropriately and the swallowed thing enters the trachea, not the esophagus. It is an important issue to prevent aspiration of especially elderly people to avoid aspiration pneumonia.
In general, aspiration is caused more frequently by aspirating saliva while asleep rather than at mealtimes. During the act of swallowing, pathogenic bacteria adhered to the saliva may enter the trachea to cause aspiration pneumonia. It is known that the patients of aspiration pneumonia show high thresholds at which to induce swallowing, that is, they hardly cause a swallowing reflex. Therefore, aspiration pneumonia can be effectively prevented by inducing a swallowing reflex to encourage proper swallowing.
As one of devices for inducing a swallowing reflex, there is known a device for facilitating swallowing by applying an electric stimulus to the patient's larynx, for example.
To suppress aspiration pneumonia, it is necessary to continuously apply an electric stimulus to the patient for a relatively long time such as during sleep hours, for example. However, if an electric stimulus is continuously and monotonically applied to the patient during that time, the application of an electric stimulus may induce swallowing in an inspiratory phase during which the patient breathes in, for example. However, when swallowing occurs in the inspiratory phase, the swallowed thing with the inspired air may enter the trachea at a higher risk, and thus aspiration may be more likely to occur.